Conditioning apparatus and compressor therefor



Jan. 22, 1957 5. E. FRANK 2,778,204

CONDITIONING APPARATUS AND COMPRESSOR THEREFOR Filed Aug. 10, 1953 I 2 Sheets-Sheet 1 Fig. 1

IN VEN T OR.

34 Bgeo rge 5, Frank:

I fi 7 cs. E. FRANK 2,778,204 CONDITIONING APPARATUS AND COMPRESSOR THEREFOR Jan. 22, 1957 2 Sheets-Sheet 2 Filed Aug. 10, 1953 Il l SLQ; N s

Rm W m m mF ,w W z 15 r fl e 7 G60 BY Unite State CONDITIONING APPARATUS AND COMPRESSGR THEREFOR This invention relates generally to an air conditioning system, and has particular reference to axial flow compressors therefor and to the construction of the stator and stator blading of such compressors.

The general object of the invention is to provide novel and efficient means for simultaneously producing a source of warm air and a source of chilled air, whereby said means may be employed both for heating and cooling purposes, or for either of such purposes.

A particular object of the invention is to provide an axial flow compressor for use as part of said means, said novel manner to deliver simultaneously two separate currents of air, one thereof chilled by rapid conduction and radiation of the heat generated during the compression, and the other being relatively warmed by the transfer thereto of such heat.

A further object of the invention is the provision of a A still further object is to provide, in such a stator structure, passages for air separate from the path of air being compressed within the structure, and means for forcing air through said passages, whereby heat generated by the compression is exchanged from the stator structure to air passing through said passages.

It is also an object of the invention to provide a novel stator structure for an axial flow compressor comprising a series of piles of thin laminae of material having high heat conductivity, certain of said piles forming stator blading stages, and other piles forming spacers therebetween.

These and other objects and features of the invention will be more fully understood from the drawing and the following more detailed description thereof.

The invention contemplates an air conditioning appaa compressor, an electric motor therefor, and an expansion motor driven by the cooled compressed air delivered by the compressor, the air discharging from the expansion motor being at a temperature considerably lower than that of the air entering the compressor.

By utilizing the compressor to deliver two separate streams of air, the heat of compression (and of friction) being exchanged from one stream to the other, not only is compressed air delivered, but a source of warm air is provided at the same time. The heat incident to compression can thus be salvaged and utilized for valuable purposes, and highly cooled air made available at the same time is delivered without the aid of relatively expensive refrigeration units, while the expansion motor not only recovers a portion of the compressed energy input but simultaneously reduces the temperature of the cooling air.

In the drawing:

Fig. l is an end view of the tion with the casing, bearing, and other usual supporting parts removed, about half the rotor impeller being broken away so that the stator structure may be more clearly shown: a

Fig. 2 is a fragmentary axial section of the compressor, with certain supporting parts removed, the first and second impellers of the rotor being shown in full, while the first and second blading structures of the stator are shown in section:

Fig. 3 is an enlarged fragmentary detail, illustrating the method employed herein for forming the stator blading structure: v v

Fig. 4 is an enlarged fragmentary detail illustrating the structure of several completely formed-stator blades, two blades being shown as they normally appears in the completed structure; while two other blades are broken away in part so that the structure may be more readily understood;

Fig. 5 is an enlarged fragmentary detail illustrating a spacer element, being one lamina of a built-up structure employed to separate the blading structures of the stator;

Fig. 6 is a diagram showing the compressor of the present invention, a drive motor for the compressor, and an expansion motor, the three structures being coaxially arranged; While Fig. 7 is a diagram showing one lamina of the first stator blading structure, one lamina of the adjacent spacer structure, one lamina of the second stator blading structure, and one lamina of the next spacer structure, as viewed compressor, partly in see- I from left to right.

The air conditioning apparatus shown diagrammatically in Fig. 6 includes a compressor iii, an air expansion motor 11, and an electric driving motor 12, the three units being arranged coaxially. For the sake of simplicity, an integral shaft 13, its right-hand end journaled in a bearing at 14, is shown as being common to the three units named.

The compressor is housed Within a casing 15, the righthand or intake end of which is open. At the'left-hand end of casing 15 and surrounding the compressed air outlet of the unitis an annular chamber 16 having an outlet 17. I

The expansion motor is housed in a casing 18, which may be conical in part, as shown. The intake or righthand end 19 of the casing 18 adjoins the left-hand or outlet end of the compressor. At the left-hand end of the expansion motor is a chamber 20 having an outlet 21.

In accordance with the present invention, the compressor 10' is so constructed that, in conjunction with the auxiliary air-driven motor 11, there are provided two separate streams of Warm and cool air which are delivered by the outlets 17 and 21 respectively. These outlets can be provided with two-way valves for delivering the heated or cooled air to a room or building for heating or cooling the same, the heated air being, if desired, discharged into the outside atmosphere during thesummer and the cooled air being similarly discharged in the winter. It will be apparent that in many industrial installations both the heated and cooled currents of air can be used simultaneously in various parts of the plant.

I have found that enough heat can be removed by conduction through the stator blades, if they are constructed in a manner described more fully hereinbelow, so that the 5 work of compression will decrease as compared to that of an ordinary, uncooled axial compressor. The heat that is removed from the compressor will be sufficient in quan-- tity and at high enough a temperature level to heat even large buildings in the winter with a relatively small com-- pressor unit. The amount of heat that from the compressed air with the aid of ture of the present invention is so large that the air dis- Patentedjan. 22,

charged bythe air expansion motor will be so much below the temperature of" the air entering the compressor that it can be used to provide cool air for dwellings and commercial buildings in the summer. The total heat energy removed from the compressed and re-expanded airby the cooling currents of air and during the work-producing expansion of the cooled, compressed air in the airmotor 18, is in fact greater in amount than the energyconsumed by the electric motor. This arises from the fact that the higher the compression ratio is raised, i. e., the larger the number of stages built intothe compressor, the greater will be the temperature difference between the heatedcompressed air within the compressor and the cooling air entering'the outer peripheral portion of the stator, whichresults in a greater heat transfer; and to this is tobe added the heat drop-in the air motor. In its totality, therefore, the apparatus operates as a heatexchanger to transferheat from one body of air to another. By suitably shaping and directing the cooling air passages, the heat transfer areaand the conditions of heat interchange can be so favorablycontrolled that the cooling air can be made to absorb practically all of the heat that the stator blades can conduct outwardly from the region of air compression.

The stator of the compressor is a laminated structure composed of alarge number of thin, discoid laminae. Thisis clearly seen in Fig. 2; the scale of Fig. 6 is so small that only the outlinesof the piles of laminae can conveniently. be shown. The laminae constituting the stator are preferably of equal outer diameter, as shown. The laminae are all perforated-in various ways, as will be explained shortly. The laminated stator structure may be held together in any suitable manner, as, for example, by rivets or bolts passed through the whole pile of'elements near the periphery of the pile. v

As shownin Fig. 6, the stator is composed of alternate piles providing blading structures and spacer structures, respectively indexed b and s. Seven blading structures separated" by six spacer structures are illustrated by way of example, the first blading structure 22 being at the right-hand end. In Fig. 2 the first and second blading structures, or piles of laminae, are respectively designated 22 and 23, and are bracketed on suchfigure. The intervening spacer structure is designated 24 and the laminae thereofare similarly bracketed. The type of construction shownin'Fig. 2 is general for the entire stator; and-the-following detailed description of the manner in which the first and second compression stages are constructed will make clear the construction of the subsequent stages.

As already indicated, the stator is composed'ofalternate pilesof laminations providing stator blading and spacers, r

the blades being disposed between adjacent stages of the compressor, While the spacers are radially in line with the rotor bladings. In accordance with the invention, the lamellae composing each stator blading are so constructed that in assembled condition they provide stator blades of the proper configuration; while in the assembled stator, the passageways for cooling air provided in the stator blading and spacer-lamcllae, are in communication with-each other to provide continuous paths for air from the inlet to the discharge side of the compressor.

Lamina 26 is seen in Fig. l to be an annular disk having alarge number of marginal perforations 27, 28 and 29; Centrally the disk is slotted-in the manner shown in Fig. l, sothata-relatively large number-of angularly spaced radial fins 39 is provided. These fins may be of generallyrec tangular outline, as shown, or they may be of somewhat tapered form. The marginal perforation pattern is preferably the same for each lamina of pile.22, but the patterns may be different, provided only that the superposed perforations constitute continuous passages from one end of the compressor to the other. However, the laminae of each pile are all different from each other in that the fins are angularly displaced circumferentially, so that the blades are angularly stepped. fromthe outer end to the-inner-end of the pile. This is clearly shown in Figs. 1, 3, and 4.

Thus the fins of the laminae of the pile form a number of blades or foils, generally designated 31, whose shape can be determined by the degree of overhang of the successive laminations.

The progressive circumferential staggering of the radial fins 39 of the successive laminae is illustratedin more detail in Figs. 3 and 4. In Fig. 3 portions of the first or outermost lamination 26 and the second or adjacent lamination 3-2 are; shown superposed. It will be noted here, as in Fig. 4, that the marginal perforations of the two laminae are in register, but that fins 30 of lamina 26 are staggered angularly with respect to fins 30' of lamina 32. In Fig; 4a portion of the entire pile.- 22 is shown, two blades 31 being shown as they appear from the outer end of the compressor. Two other blades are" illustrated with some of their fins 30 broken away so that the staggered constructions may be readily seen.

In the spacer piles, such as the pile 24 shown in Fig. 2, which separates the blade-forming piles 22 and 23, all the-laminations are exactly alike. Each lamina is provided with a circular central opening, and is thus in the form of an annulus having perforations-27', 28, and 29' which are registered with like perforations in all the other laminae of the stator structure. A part of a typical lamina 33 of pile 24''. is shown in Fig. 5'. It will be understood that the pile 24 not onlyseparates the first and second blading structures but also provides a hollow cylindrical space 34 (see Figs. 2 and 5) within which the second impeller 35 of the. rotor mayrotate.

The second stator'blading structure, comprising pile 2'3, is. constructed in the manner of pile 22, but while the laminae. of pile 23 have an-outer diameter equal to that of allof'the other laminae of the stator structure, and have marginal perforations, 28, and 29in register with like perforations in the other laminae of theentire'structure, the central opening of the laminae-of pile 23 is smaller in diameter than that of thelaminae of pile 22', and, consequently, its fins 30 are shorter than the fins of the laminae of the first-stator blading pile, so as to provide a compression stage.

Thus. the entire, stator structure comprises a series of piles or groups of laminae or annular disks forming blading structures separated by spacer structures, the central openings'of thelaminae of the spacer piles progressively decreasing in diameter from the inlet end to the outlet end of the compressor. Also, the impellers of the rotor correspondingly decrease in diameter inthe same direction. See Figs. 6- and 7. In-the latter figure, four laminae, each assumed to be an element of different consecutive piles, are. schematically indicated. It will be noted that. the marginal perforations of all laminae here shown are alike; and that: the lefthand element 36, which is part of a blading pile, has a longer fin length than element 37, which is part of the next blading pile ofa higher pressure stage. Element 38, between elements 3.6. and 37, is part of the. spacer pile separating the-two blading piles. It will.be noted that its central circular opening is of greater diameter than that of element 39, to therighhwhich is part of the next spacer pile. From the foregoing, the generalarrangement of laminae of the entire stator structure will be. readily understood.

As best shown in Figs..1. and 2, the first'impeller 25 of the rotoris; provided withblades long enough to extend nearly: to the. periphery of. the. stator structure; Asthe rotor turns, as indicated by the. arrow. about the shaft in Fig. 2, air is. blown not only into the compressor stages. of the unit but alsothrough the considerable number of passages provided by the registered marginal perforations 27, Miami 29 of. the laminae of the stator. Arrows in Figs. 2v and 6 indicate the direction of, flow through the perforations. In Figs. 2. and-6, for passages 40 andAl, are shown in axial section.

In the form of the. invention illustrated, the. first impeller 25' isthe only one which forces. air through the.

passages provided'in the outer part of the stator structure,

The other impellers are stepped in the usual manner to accord with the stages of the compressor. The generated compressed air passes from the compressor into the expansion motor, and thence into chamber 20 and out through outlet 21. Air blown through the passages, such as 40 and 41, is collected in chamber 16 and passes therefrom through outlet 17. No details of the expansion motor are shown, as these are well understood in the art. The rotor blades of the expansion motor are indicated at i.

The laminae of which the compressor stator is constructed are preferably of aluminum or other metal having high heat conductivity. Heat generated by compression of air being forced through the compressor is conducted outwardly by means of the fins of the stator blading structures. As will be evident, since the blades are made of a plurality of staggered fins, an escalated foil surface is presented to the air being blown through the compressor, whereby a much greater surface for the transfer of heat is presented than would be the case were the blades smooth. Heat conducted outwardly by the fins of the various laminae to the marginal portions thereof is transferred to the streams of air flowing through the passages, such as do and 41, so that the air collected in chamber 16 and passing through outlet 17 contains a large proportion of the heat generated within the compressor. Also, as the heat of compression is rapidly and efilciently conducted away from the compressed air, such air enters the expansion motor relatively cool, so that the expansion therein chills it to a temperature considerably below the compressor inlet temperature.

Thus the apparatus provides simultaneously a source of warm air and a source of cool air for heating and cooling purposes respectively.

The laminae of which the stator is constructed are preferably as thin as may be without impairment of rigidity sufiicient to withstand the flow of gas in the compressor. However, they may be made considerably thicker, if desired. The amount of stagger of adjacent laminae of a blading structure is preferably such that the average width of the step so provided is about equal to the thickness of the air boundary layer. The circumferential staggering of the laminae of a blading pile need not be uniform, but may be so varied that a properly curved aerodynamic foil is provided.

It will be seen from the foregoing, that I have provided a heat exchanging axial compressor having an improved construction of air foil blading which promotes the rapid removal of the heat of compression (and'also heat of friction within the compressor) through the stator blading to the outer mass or shell of the stator. The stator is advantageously built up of a plurality of metal stampings having perforations for cooling air which are of relatively small cross-section and are large in number, so as to provide a maximum of heat transfer surface. The laminae or plates are preferably about /2 mm. thick, and should be capable of being bent to give the blades the desired aerodynamic outline. This aerodynamic outline can be preliminarily formed by employing piles or packs of laminae, as above described, wherein the fins 31} of successive laminae in each pack are angularly offset with respect to each other, such olfsetting being approximately /2 to 1 mm.

The piles or packs can, however, be built up also of laminae which are identical in every respect and which, after being stacked in complete registry with each other, are then angularly offset in relation to each other, to give the fins the curved form of the desired aerodynamic foil. In such case, the passageways for the coo-ling air will not run axially, and the perforations should be so spaced angularly in the case of both the blade-forming laminae and the spacer laminae that continuous although more or less sinuous passages for the cooling air are 6 provided. This sinuous path is desirable as it causes turbulence which improves the rate of heat transfer.

The profiles of the blades can be correctly proportioned and filled out by varying the thickness or width of the fins in the successive annular laminae. It is of advantage to proportion the fins in such manner that the crosssection of flow area between the inwardly extending fins will be about equal to the area of the perforations in the outer portion of the laminae.

The stepped construction of the stator blades causes a high degree of turbulence at the surface of the blades and thus prevents the formation of a static insulating layer of air, so that the rate of heat transfer at the blades is increased.

With the above described construction, enough heat can be removed by conduction through the stator blades, and by radiation from the rotor shaft and blading, to effect a considerable decrease in the work of compression as compared with the usual uncooled axial compressor.

This heat will be removed at a temperature level sufficiently high to heat dwellings and other buildings in the winter. It will be understood that such heat is not all derived originally from the work or energy input of the electric motor, but is obtained in large part from the air Which is discharged at sub-atmospheric temperature from the expansion motor or turbine. The temperature of the air discharging from the air-driven motor or turbine can be reduced still further by increasing the compression ratio of the compressor, as then higher temperatures are generated in the compressor with the result that larger quantities of heat are withdrawn by the cooling air by reason of the increased temperature differential between the compressed air and such cooling air.

The expanded and cooled air can be utilized for cooling purposes in buildings of various kinds in the summer, or for industrial operations.

Since the heat transfer surface in the cooling passages is determined by the perimeters of the perforations, such surface can be made very large by providing a large number of perforations, so that it is possible to remove with the cooling air practically all the heat that the stator blades can conduct outwardly and likewise the heat received by the spacer laminae, both from contact with the compressed air and by radiation from the rotor blades.

It is desirable to make the compressor with a large number of stages, as many as 20 stages being practicable. Thecompressor is generally driven at relatively low speed, as by a synchronous motor at about 3600 R. P. M., which is a very low speed for axial compressors.

Since the expansion motor aids the electric motor in driving the compressor, the power intake of the electric motor, and hence the cost of operation, are reduced.

When the air charged into the compressor is at or near saturation,condensation may take place in the expansion motor owing to the cooling of the air below the compressor intake temperature. Some of this moisture may collect in the expansion motor, and to remove the same, there may be provided bottom of chamber MB for collecting and water. Such trap can be drained through a float-operated valve or the like operating automatically. As the structure of such trap and valve are well understood by persons skilled in the art, they have not been illustrated.

Should it be desired to insure that the cooled air discharged by the air motor 13, of a moisture content markedly below saturation, this can be accomplished by arranging a compressor of only one or two stages or so after the air motor, the suction side of such additional compressor being connected to the discharge end of the air motor. The air will in such case be expanded in the air motor to a pressure below atmospheric and to a correspondingly lower temperature, and additional moisture will then separate out in the air motor. This superdischarging the a trap, say at the i expanded air will then be recompressed'to atmospheric pressure with some elevation of the temperature thereof, but still .below the surrounding air temperature and will be unsaturated, so that it will provide greater comtort when provided for cooling purposes in the summer.

So far as I am aware, the general organization ofparts shown in Fig. 6, wherein the compressed air is vigorously cooled and the cooled air employed to operate a. motor which is arranged to aid in the drive of the compressor, is new without reference to the specific construction of the stator blading and spacer laminae, and I therefore claim as within the scope of my invention the combination of parts illustrated in Fig. 6 without limitation to the manner in which the air cooling passages and the stator blading are formed.

Variations in combinations and sub-combinations herein disclosed may accordingly be resorted to within the scope of the appended claims without departing from the spirit of the invention.

Thus, the cooling air can be made to travel through the stator of the compressor in counter-current relation to the air being compressed therein; and to prevent the heated cooling air in such case from. losing heat to the air being charged into the compressor at the inlet end of the latter, the lead-off for the heated cooling air can be arranged at an intermediate point of the compressor stator, in which case the inlet end portion of the stator will not be provided with air cooling passages.

I claim:

1. An air conditioning system comprising an axial air compressor, a motor for driving the compressor, means comprising substantially axially extending air passageways in the stator of the compressor, means for directing cooling air into said passageways for cooling the compressed air through heat exchange relation within the compressor with a current of relatively cool air, said passageways being substantially coextensive with the stator blading, a compressed air motor arranged to aid inthe drive of the compressor, the latter discharging the cooled, compressed air into the air motor for expansion therein, and separate discharge conduits for the heated cooling air and the cooled expanded air.

2. An air conditioning system as defined in claim 1, wherein the stator of the axial air compressor is constructed for maximum transfer of the heat of compression to the cooling air and comprises a plurality of blade carrying units and of spacer units secured to each other to provide a rigid stator structure, at least the bladecarrying units of the stator being each composed of a plurality oflaminae lying in planes transverse to the rotor axis of the compressor, said laminae and said spaced units being provided with perforations which are in registry to provide the said air passageways, the laminae of the blade-carrying units being provided with inwardly extending radial fins which are successively angularly disposed in each unit to provide stator blades of aerodynamic outline.

3. An air conditioning system as defined in claim 2, wherein the laminae of the blade-carrying units are constituted of identical metal stampings of high heat conductivity-whereby the passageways formed by the registering perforations in the laminae run at an angle to the axis of the compressor.

4; An air conditioning system as defined in claim 1, wherein the rotor of thecompressor is provided at its inlet end with blading of sufficient length to force air through the air passageways.

51 An axial compressor comprising a rotor and a stator, the stator being composed of a plurality of bladecarrying units and of spacer units secured to each other to provide a rigid stator structure, at least the bladecarrying units of the stator being each composed of a plurality-o. laminae, said laminae and said spacer units being provided with perforations adapted to be placed in registryto provide air passageways for the cooling of theair being compressed in the compressor, and means.

.for forcing air through the said passageways, the laminae of the blade-carrying units being provided with inwardly extending radial fins which are successively angularly displaced in each unit to provide stator blades ofaerodynamic outline.

6. An axial compressor comprising a rotor and a stator, the stator being composed of a plurality of bladeoarrying units and of spacer units secured to each other to provide .a rigid stator structure, at least the bladecarrying units of the stator being each composed of a lurality of laminae, said laminae and said spacer units being provided with perforations adapted to be placed in registry to provide air passageways for the cooling of the air being compressed in the compressor, and means for forcing air through the said passageways, the laminae of each blade-carrying unit being constituted of identical metal stampings of high heat. conductivity which are angularly displaced to provide blades of aerodynamic outline, whereby the passageways formed by the perforations in the laminae run at an angle to the axis of the compressor.

7. An axial compressor comprising a rotor and a stator, the stator being composed of a plurality of bladecarrying units and of spacer units secured to each other to provide a rigid stator structure, at least the bladecarrying units of the stator being each composed of a plurality of laminae, said laminae and said spacer units being provided with perforations adapted to be placed in registry to provide air passageways for the cooling of the air being compressed in the compressor, and means for forcing air through the said passageways, the laminae of the blade-carrying units comprising metal stampings of high heat conductivity provided with the said perforations in the body thereof and having inwardly extending radial fins, the tins of successive laminae being angularly displaced so that when the perforations of the laminae of a group are disposed in axial registry, the fins will form blades of approximately aerodynamic outline.

8. An axial compressor comprising a rotor and a stator, the stator being composed of a plurality of bladecarrying units and of spacer units secured to each other to provide a rigid stator structure, the spacer units being each composed of. a plurality of annular laminae provided with numerous perforations for the passage of air therethrough, said blade-carrying units being each similarly composed of a plurality of annular laminae, said last mentioned laminae having angularly spaced inwardly extending radial fins adapted to form the stator blades; said last mentioned laminae having numerous perforations communicating with each other and with the perforations in the laminae of the spacer units, and means for forcing cooling air through the passageways formed by such perforations, said laminae being formed of sheet metal stampings of high heat conductivity.

9. A compressor as defined in claim 8, wherein the means for forcing air through the passageways comprises an impeller on the rotor having blades extending to the inlet openings of. the passageways.

10. A compressor as defined in claim 8, wherein the registering perforations are so disposed that the air passageways extend parallel to the compressor axis.

11. A compressor as defined in claim 8, wherein the perforations in the successive laminae are so disposed that the air passageways form non-rectilinear paths for the cooling air.

12. The method of making a stator blading, which comprises arranging a series of laminae one behind the other, each of said laminae being centrally slotted to provide a plurality of angularly spaced, radial blade elements; angularly staggering the laminae to form blades which are angularly disposed with reference to the central axis and are of approximately aerodynamic outline; and securing the laminae to each other.

13. The method of making stator blading for axial fiow' machines wherein said blading is utilized to conduct heat from the interior of the machine, which comprises arranging a series of metallic laminae one behind the other, each of said laminae being centrally slotted to provide a plurality of angularly spaced, radial blade elements; angularly staggering the laminae to form the blade elements into a series of blades of approximately aerodynamic outline with their stepped lateral surfaces extending at an angle to the axis of the laminae; securing the laminae to each other; and forming a plurality of air passageways in said laminae outwardly with respect to said elements.

References Cited in the file of this patent UNITED STATES PATENTS 1,265,650 Graemiger May 7, 1918 10 Kuyser Jan. 27, 1920 Stalker Mar. 16, 1943 Lysholm Aug. 3, 1943 Peterson Oct. 31, 1950 Kane Nov. 18, 1952 Curry Dec. 2, 1952 FOREIGN PATENTS Great Britain Apr. 15, 1953 France July 13, 1951 

